Persons traveling on transit vehicles in mass transit systems such as air or ground vehicle transportation systems pass through transit stations. Broadly, these transit stations provide central locations for the transit vehicles to embark and disembark passengers as the persons travel from an originating station to a destination station as well as passing through intermediate transit stations for the person to transfer from one transit vehicle to another on the trip. Announcement devices are used at the transit stations and in the transit vehicles for guiding the persons to appropriate gates for traveling on the appropriate transit vehicle. These announcement devices include travel message boards, video displays, and audio announcements broadcast in terminals and transit vehicles over loudspeakers. Multiple language announcements typically are presented serially on display boards, aurally, or in combination. Generally, there is a time restriction on announcements due to the number of announcements that must be made. Further, the number of different languages restricts the time available for any one particular announcement. The shorter the amount of available time, the fewer the number of languages or the shorter the message in the announcement. Also, passengers may not be aware of display messages, by not being in the vicinity of the display or being blocked from viewing the display.
Many large commercial airport transit stations use high capacity moveable vehicles to carry passengers among the several concourses having gates to which the passengers move for boarding aircraft. These movable vehicles have a variety of forms, including trains of interconnected cars, buses, and the like. Typically, these vehicles have open interiors with minimal seating. This increases the capacity of the vehicles without significant inconvenience to the passengers who stand as the vehicle travels a predetermined route from concourse to concourse. Generally, the concourses have unique identifiers, so that the passengers can locate the particular aircraft for the planned travel. The vehicles have devices onboard for advising the passengers of the transit stop for the concourse at which the vehicle is arriving. Often the concourses are close together. With the increasing number of international and foreign travelers, announcements of transit stops often are made in different languages. In typical transit stations serving international travelers, announcements are made in English, Spanish, French, and Japanese. While the announcements are typically of short duration because limited information is to be communicated, specific language requirements dictate that the announcement in one language is of longer duration than in other languages. Depending on the interval between transit stations, an announcement may not provide sufficient time for passengers hearing the message in their language to react and depart from the vehicle. The announcement may be rushed or shortened, and thereby not communicate effectively with the passengers. Communication of aural messages involves a listener's capability to localize and discriminate auditory events, to distinguish the effect of when and where auditory events including initial sounds and subsequent echoes, and to focus on one of many auditory events occurring simultaneously. The ability to localize auditory events separated in three-dimensional space enables listeners to discriminate the auditory events. The Duplex theory suggests that listeners experience both interaural time differences, or time delays when sounds reach one ear before the other, and interaural intensity differences, or intensity differences in sounds reaching the ears as a result of head orientation. Further, the shapes of the outer ears (the pinea) also affect sound localization whereby the listener determines the location of the source of the sound. Localization is also dependent upon physical characteristics such as shoulder echo, head motion, early echo response, reverberation, atmospheric absorption, bone conduction, and prior knowledge by a listener of the sound source. The precedence effect relates to when and where auditory events are first perceived. This influences the listener's belief as to the direction of origination of the sounds. Precedence helps listeners distinguish between original sounds and subsequent echoes or reverberation. Further, listeners generally have an ability to detect, discriminate, and focus on one selected voice communicating sounds among many such voices. This ability may be described as the cocktail party effect, whereby a listener focuses on one of many voices. Factors affecting the ability to filter unwanted speech or noise and thus aid in focusing on a single voice include spatial separation, modulation of speech or sounds, and visual cues. For example, studies have shown that listeners could more readily focus on a desired voice among many when loudspeakers were disposed at 90° azimuth relative to the listener. Other discrimination effects are noted with low- and high-filtering, such as at 1.6 kHz. U.S. Pat. No. 5,438,623 describes a device that spatilizes messages communicated to listeners wearing headphones to four virtual auditory positions, so that the listeners can more easily focus on one of the four simultaneously presented voice channels. However, such is impractical for open-field environments and requires processing of monophonic sounds in real-time with digital signal processors to create spatially separate virtual sounds. Accordingly, there is a need in the art for an improved apparatus and method of communicating messages to persons using transit systems. It is to such that the present invention is directed.